HG-AFS法检测海带提取物中无机砷含量的样品前处理方法研究

Study on the method of pretreatment for determination of inorganic arsenic in kelp extracts by hydride generation atomic fluorescence spectrometer

以氢化物发生原子荧光光谱法（HG-AFS）为检测手段,研究了一套检测海带提取物中无机砷含量的样品前处理方法。文中比较了三种前处理方法：蒸干溶剂法、更换溶剂法及萃取法,结果表明：更换溶剂法稳定、准确、方便,该法以乙醇-水体系提取的海带提取物为检测对象,在低温中性条件下蒸去样品中的乙醇,使提取物中干扰检测的有机物缓慢析出而亲水性无机砷逐渐转入剩余的水层,将分离水层作为检测样液。本方法的RSD%为1.30%-2.63%,加标回收率为90.97%-95.02%。与传统的前处理方法相比,本法的条件更为温和,有利于防止海藻中的有机砷在苛刻条件下水解为无机砷,因而改善了检测结果的可信度。

A sample pretreatment method to detect inorganic arsenic in kelp is developed. In this method,kelps extract is obtained by using an alcohol-water system assisted by microwave irradiation. Alcohol in the extracts is subsequently removed through the vacuum distillation at 60 ℃ and p H at 7. Through this method,inorganic arsenic is separated and enriched in the aqueous phase which is then detected by the hydride generation atomic fluorescence detection（HG-AFS）. This method was simple and rapid. And the recovery of this method ranged from 90.97% to 95.02 % with the RSDs less than 2.63 %. This approach demonstrates a high accuracy in the trace inorganic arsenic analysis over conventional method.